A conventional electrical connecting apparatus A of this kind includes a wiring base plate 1 made of, e.g., a printed circuit board (PCB) and a probe base plate 2 arranged to be spaced from a lower surface of the wiring base plate and provided on a lower surface thereof which is an opposite side of a surface opposed to the wiring base plate 1 with multiple probes 2a as illustrated in FIG. 5 (for example, refer to Patent Literature 1). Between the wiring base plate 1 and the probe base plate 2 is arranged an interposer 3 made of an elastic connector such as a pogo pin assembly, and the respective probes 2a of the probe base plate 2 are electrically connected to sockets (not illustrated) provided on the wiring base plate 1 via the interposer. The electrical connecting apparatus is connected to a tester main body (not illustrated) at the sockets. On an upper surface of the wiring base plate 1 is provided a reinforcing plate 4 adapted to restrict warpage of the wiring base plate 1. The reinforcing plate 4, the wiring base plate 1, the interposer 3, and the probe base plate 2 are coupled integrally by tightening of bolts 5 to be inserted from a side of the reinforcing plate 4.
More specifically, tip ends of the bolts 5 inserted from an upper surface of the reinforcing plate 4 are screwed in anchor portions 2b provided on the probe base plate 2 and are tightened. Also, cylindrical spacer members 6 are attached to the bolts 5 and determine a height position of a virtual plane P on which probe tip positions of the respective probes 2a are aligned in cooperation with the anchor portions 2b in which the tip ends of the bolts 5 are screwed when the bolts 5 are tightened.
In an electrical test of a device under test 7 with use of the electrical connecting apparatus A such as a probe card, an edge portion of the wiring base plate 1 is mounted on an upper surface of an edge portion of a card holder 8 provided in a test head of the not illustrated tester, and probe tips of the respective probes 2a abut on corresponding electrodes 7a of the device under test 7 on a stage Y. At this time, in order for the respective probes 2a to contact the corresponding electrodes 7a with uniform and appropriate thrusting forces, a length L3 of each spacer member 6 is selected in accordance with a manufacturing error of a thickness dimension L1 of the wiring base plate 1, for example, so that a distance from the upper surface of the edge portion of the card holder 8 to the virtual plane P on which the probe tips of the respective probes 2a are aligned may be a predetermined value L.
Also, by thickness adjustment of a shim 9 to be inserted between the wiring base plate 1 and the reinforcing plate 4, the height position of the virtual plane P on which the probe tips of the respective probes 2a are aligned is finely adjusted.